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Potato plants with symptoms suggestive of potato purple top disease (PPTD) occurred in the central, western and north-western regions of Iran. Polymerase chain reaction (PCR) and nested PCR assays were performed using phytoplasma universal primer pair P1 ⁄ P7 followed by primer pairs R16F2n ⁄ R16R2 and fU5 ⁄ rU3 for phytoplasma detection. Using primer pairs R16F2n ⁄ R16R2 and fU5 ⁄ rU3 in nested PCR, the expected fragments were amplified from 53% of symptomatic potatoes. Restriction fragment length polymorphism (RFLP) analysis using AluI, CfoI, EcoRI, KpnI, HindIII, MseI, RsaI and TaqI restriction enzymes confirmed that different phytoplasma isolates caused PPTD in several Iranian potato-growing areas. Sequences analysis of partial 16S rRNA gene amplified by nested PCR indicated that ÔCandidatus Phytoplasma solaniÕ, ÔCa. Phytoplasma astrisÕ and ÔCa. Phytoplasma trifoliiÕ are prevalent in potato plants showing PPTD symptoms in the production areas of central, western and north-western regions of Iran, although ÔCa. Phytoplasma solaniÕ is more prevalent than other phytoplasmas. This is the first report of phytoplasmas related to ÔCa. Phytoplasma astrisÕ, ÔCa. Phytoplasma solaniÕ and ÔCa. Phytoplasma trifoliiÕ causing PPTD in Iran.

Potato plants showing symptoms suggestive of potato witchesÕ-broom disease including witchesÕ-broom, little leaf, stunting, yellowing and swollen shoots formation in tubers were observed in the central Iran. For phytoplasma detection, Polymerase Chain Reaction (PCR) and nested PCR assays were performed using phytoplasma universal primer pair P1⁄P7, followed by primer pair R16F2n⁄R16R2. Random fragment length polymorphism analysis of potato phytoplasma isolates collected from different production areas using the CfoI restriction enzyme indicated that potato witchesÕ-broom phytoplasma isolate (PoWB) is genetically different from phytoplasmas associated with potato purple top disease in Iran. Sequence analysis of the partial 16S rRNA gene amplified by nested PCR indicated that ÔCandidatus Phytoplasma trifoliiÕ is associated with potato witchesÕ-broom disease in Iran. This is the first report of potato witchesÕ-broom disease in Iran.

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